Apparatus for manufacturing rubber boots



Dec. 29, 1964 A. SILOMBRA 3,162,875

APPARATUS FOR MANUFACTURING RUBBER BOOTS Original Filed July 10, 1961 4 Sheets-Sheet 1 Dec. 29, 1964 A. SILOMBRA 3,162,875

I APPARATUS FOR MANUFACTURING RUBBER BOOTS Original Filed July 10. 1961 T 4 Sheets-Sheet 2 Dec. 29, 1964 A. SILOMBRA 3,162,875

' APPARATUS FOR MANUFACTURING RUBBER BOOTS Original Filed July 10, 1961 4 Sheets-Sheet 3 s2 5s s3 s1 54 Dec. 29, 1964 APPARATUS FOR MANUFACTURING RUBBER BOOTS Original Filed July 10. 1961 Fig.

A. SILOMBRA 3,162,875-

4 Sheets-Sheet 4 v United States Patent 2 Claims. ci. 12-1 This invention relates to an apparatus for making rubber boots, and is a division of application Serial No. 122,779, filed July 10, 1961.

Hitherto, the usual practice consisted in placing the boot components on lasts carried by an endless conveyor from one'operator to another for successive lasting of the lining, upper and sole. The lasting step was followed by manual pressing or rolling of said boot components against the last in order to insure satisfactory adherence of the components as well as eliminate, as far as possible, air pockets trapped between the last surface and superimposed boot components. The lasted boots were then taken off the conveyor, placed on suitable racks and put in batches into an autoclave for vulcanizing. As manual pressing was insufiicient to eliminate all air pockets, blisters were formed on the boot walls when the temperature in the autoclave was raised, so that each last, which was ac cordingly made hollow, had to be connected through a suitable piping provided in the racks to a suction pump which sucked air from the last cavities while vulcanizing was in progress.

The main drawback of the method including sucking air from batches of lasted boots already in the autoclave, consists in the large number of lasts connected to the suction piping in the racks, which in turn had to be connected through a conduit extending externally of the autoclave to a pump.

Air leakage from the autoclave through each joint counteracted the action of the suction .pump so that a lower suction, if any, was exerted on the lasts connected further down the conduit, resulting in the formation of said blisters, hence faulty product.

An object of this invention is to provide an apparatus for manufacturing rubber boots wherein the operation of manual pressing or rolling of lasted boots is dispensed with and replaced by a uniform compression applied pneumatically by setting up during a predetermined period of time a sub-atmospheric pressure in the last cavity to afford a speedier and cheaper manufacture of a considerably improved product.

Another object of this invention is to obviate the necessity of applying suction to the lasts with boots thereon, after the latter have been introduced into an autoclave for vulcanizing.

The above and other objects of the invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example a preferred embodiment.

Referring to the drawings:

FIGURE 1 is a diagrammatic plan view of the conveyor and distributor;

FIGURE 2 is an enlarged plan view of the distributor and return end of the conveyor;

FIGURE 3 is a part-sectional side view of the last supporting jack;

FIGURE 4 is a sectional view on line IV-,IV of the FIGURE 3;

FIGURE 5 is part-sectional side view of the last with an assembled boot thereon;

FIGURE 6 is a sectional view on line VI-VI of FIG- URE 2 showing one hose of the distributor in its raised condition;

3,l62,875 Patented Dec. 29, 1964 FIGURE 7 is a sectional view on line VIIVII of FIGURE 2; and

FIGURE 8 is a diagrammatical part-sectional view of the air conduits and electrical connections of the distributor.

An elongated bench 1 is supported by a substructure 2. Suspended peripherally of said bench is an endless conveyor comprising a guide rail 3 of I-section on which a plurality of uniformly spaced last supporting jacks 4 are carried along from one operator to another by means of an endless chain 5 suspended from said jacks. The chain '5 travels around two sprocket wheels 6, 7 situated at the ends of the bench 1. The wheel 6 may be driven at a desired speed by a greared motor 8, wheel 7 being a reversing gear provided with a chain tensioning device, not shown.

Situated internally of the reversing loop of the conveyor is an air suction distributing device 9, having a plurality of radially extending arms arranged at an angular pitch matching the angular pitch of jacks 4 when the latter travel over the reversing wheel 7. By means of this distribu'ting device, a sub-atmospheric pressure is set up in each last at the reversing loop of the conveyor. Each jack 4 comprises a body 10 provided at its lower portion with one vertical roller 11, a pair of horizontal rollers 12, and a fork 13 for fixing the jack to one of the cleats 14 fastened at regular intervals to the chain 5. The vertical roller 11 has a flange 11a and each horizontal roller 12 includes two flanges 12a. These flanges guide their respective rollers 11 and 12 on the guide rail 3. The upper portion of the body 16 is formed with an air passageway 15 leading to an opening 16 in the upper face of the body 10, and an opening 17 in the lateral, outwardly turned face of said body. The portion of the passageway 15 adjacent the opening '16 is flared out to form a conical seat 18. The opposite end portion of the passageway 15 is threaded at 19 to receive the threaded portion of a hollow pin 20 having a conical head 21 mounted in free relationship thereon. The head 21 is provided intermediate the length with an external circumferential groove to accommodate a sealing ring 22.

Supported by a tubular extension 10a on the body 10 and spaced from the conical head 21 is a quick-release last engaging snap lock comprising a spring-loaded axially siideable rod 23. FIG. 4, having a large diameter portion 2 4- and a small diameter portion 25 ending by a knob 26. The rod 23 is urged by a spring 27 to its extended position and can be depressed by manual action on the knob 26.

Intermediate the length of the rod 23 a catch plate 28 is pivoted at 29 in a slot in the body extension ltla. A tip 28a of the catch plate protrudes: past the rod 23 towards the conical head 21. A spring 30 urges the catch plate 28 against the rod, so that the plate locks the rod when the latteris depressed and releases the rod when the tip 28a is pressed against the action of the spring 30.

A last 31, FIG. 5, adapted to be detachably connected to the jack 4 comprises a hollow boot-shaped portion 32 formed by a wall having perforations 33. The boot shaped portion 32 is formed at its end opposite the sole end with a longitudinal cylindrical boss 34 having a concentrical conical cavity 35 communicating with the cavity in the last and complementary to the conical head 21. lntermedia-tely its length, the boss 34 is formed with an external circumferential groove 36 which, when the last 31 is connected to the jack 4, registers with the large diameter portion 24 on the rod 23, to thereby lock the last on the jack and at the same time allow free rotation around the pin 20 of the last supported by the conical head 21. When the last is connected to the jack, the sealing ring 22 forced into its groove by the wall of the conical cavity 15 improves air tightness of the joint.

greases In order to disconnect the last 31 from the jack 4, the

knob 26 is manually depressed until the large diameter head 21 so that the boss end presses the tip 28a on the catch plate 28 causing release of the rod 23, which is urged upwardly by the spring 30 and engages the groove 36.

The air suction distributing device 9 is mounted on a vertical stationary support, comprising a tube 37, FIG. 8, having its bottom end sealed and formed with a suitable base 38 for attachment to the table 1. At its base end the tube 37 is connected by means of a tube 39 to a suction conduit on a pump 46. At its base end the tube 37 is moreover formed with a lateral opening closed by a bored plug 41'. The top end of the tube 37 is sealed by means of a bored plug 42 provided externally with a prismatic projection 43, FIG. 7.

Fixed on the projection 43 is'a stationary cam 44 hav- 7 ing a circular profile 4-5 extending through over half the circumference and a rectilinear closing profile 4-6. The cam is oriented with its circular profile facing the reversing loop of the conveyor. Above the cam 44 a circular electric current distributor 47 is fixed to the projection 43 by means of an insulating bushing 43. The top end portion of the tube 37 forms a spindle d9 provided intermediate its length with radially arranged holes 50.

A hub 51 formed internally with a cavity 52 and having four radially extending tubular arms 53 communicating with the cavity 52 is mounted on the spindle 49 by means of ball bearings 54, 55, so that the cavity 52 is aligned with the holes 5%. The hub 51 is sealed against the spindle 49 by 'two sealing rings 56, 57 sealing the cavity 52 from the atmosphere. Each arm 53 is provided with a lifting tube 58 connected to a downwardly looping flexible hose 59 having 7 a downwardly extending branch 59a extending through a guide ring 62 fixed to an extension 63 on the arm 53, 1 16.6. The branch 59a is provided at its free end with a metallic nozzle 6% of a conical shape complementary to the conical seat 18 in the jack d. The nozzle is provided at its large end with a radially extending flexible disc washer 61, FIG. 8.

The weight of the nozzle 69 and theportion of the hose 59 is supported by an oscillating arm 64 pivoted at 65 to the hub 51 and provided with a clamp dda for clamping the hose 59. The arm 64 is held in its raised position by the action of a spring 66.

The nozzle tl can be lowered manually by pulling down the hose branch 59a against the action of the spring 66. When the nozzle 66 is lowered it can be inserted.

into the seat 18.

The air flow through each hose 59 is governed by a solenoid controlled cut-off valve 67 arranged on each arm 53, FIG. 8. The valve 67 is jointly operated by a switch controlled by the cam 44 and by the insertion of the nozzle 69 into the seat 13.

For this purpose the distributor is provided with an electric control system comprising a step-down transformer 65 having its primary winding connected to a power supply (not shown). One end of the secondary winding is grounded at 69, its other end connected at 70 to the current distributor 47 by means of a lead 71 extending through the tube 37 and in an air-tight manner through the bore in both plugs 41 and 42;, FIG. 8.

Supported by the hub 51 are four step-down transformers 72, the primary windings of which are connected in parallel to the secondary windings on the transformer 6% by means of brushes 73 contacting the distributor 4'7 and by a ground connection 74.

A solenoid 75 on each valve 67 is grounded at 76 and is connected to the primary winding of its respective v transformer '72 by means of a lead 77 controlled by a relay '78 energized by the secondary: winding of the trans former 72. One end ofthe secondary winding of the transformer 72 is connected to the nozzle 6%) by means'ot a flexible lead 79 extending through the hose 59 the other end of said secondary winding being connected by a lead 80 to the coil of relay '78 grounded at iii. The lead at has series connected therein a circuit cut-out switch 82 operated by cam 44 through a follower 33 supported from the hub 51.

The relay 78 can be energized to close the circuit of the solenoid 75 only when its respective follower 33 contacts the circular profile 45 on the cam 44, thereby closing the cut-out switch 82, the circuit is completed when a respective nozzle 6%) is grounded by insertion into a body 10. Such a condition occurs only on such arms onthe distributor 9 as are located in the sweep of the angle CDE, FIG. 2, determined by the imaginary radii ofthe earned extending through the end points on the circular profile 45 and intersecting the center line of the guide rail 3 at points C and D, respectively. A suitable hood 87, FIG. 7, may be fixed to the extension 43 for protection of the electrical installation mounted on the hub 51.

The operation of the above-described apparatus is as follows. Assumingtheendless conveyor travels in the direction of the arrow f, FIG. 1, an operator situated at point A inserts a last on the jack 4 and pulls on a sewn-up lining 84, FIG. 5. Further operators spaced round the conveyor between points A and B fasten by gluing onto the lining an upper 85 and a sole 86 in a sequence of operations taking advantage of the rotational mounting of the last on the jack. The operator at point B lrnurls the seams of the boots and inserts the nozzle 60 into the seat 13 of the passageway 15, after the jack 4,

' passes over the point C on the conveyor. Insertion of the nozzle effects opening of the valve 67 and establishes interconnection of the pump 49 and last, whereby the pump d0 sucks air from the last'cavity. v This causes the atmospheric pressure to compress the boot against the last and the washer 61 against'the jack face around the opening 16, sealing the joint and providing a force which prevents the spring 66 from raising the arm 64 and disconnecting the nozzle oil from seat 13. Travelling around the reversal loop of the conveyor the jack 4 pulls the hose 59a thereby rotating the distributor 9.. The last is subjected to suction during a predetermined period or" time necessary for the air trapped between the boot and last to seep through the lining $4 and perforations 53 into the last cavity.

When the jack reaches point B the cam operated cutout opens the circuit causing the valve 67 to close. Atmospheric air leaks through imperfect joints into the last cavity, equalizer. the pressure and counterbalances the atmospheric pressure on the washer 61, causing the spring 6% to raise the arm 64 and hose 59a, thereby disconnecting the nozzle 60 from the seat 18.

The'distributor is now rotated by a further jack on the conveyor, the disconnected hose proceeding towards the point C ready for connection to an incoming jack. After passing the point B the jack passes an operator at F who inspects the boot, depresses the knob 26, pulls the lasts oh the jacks and places them on racks for delivery in batches to anautoclave for vulcanizing.

While a preferred embodiment of the invention has been described and illustrated, it will be understood that modifications of constructional details and arrangement of parts may suggest themselves to those skilled in the art, V

passageway in each of said jacks, means for detachably connecting the last cavities to said passageways, a suction pump and distributing means for detachably connecting said pump to said passageway on at least one of said jacks.

2. An apparatus as claimed in claim 1, wherein said distributing means comprise a stationary hollow support situated internally of said reversing loop of the conveyor and connected to the suction pump, a hollow hub, a plurality of tubular arms carried by said hub, said hub sealingly mounted in free rotational relationship on said support and having its inside communicating with the inside of said stationary hollow support, a flexible hose connected to each of said tubular arms and a nozzle at the free end of each hose for detachably connecting said hose with the air passageway in a selected jack passing the said reversing loop of the conveyor.

References Cited by the Examiner UNITED STATES PATENTS JORDAN FRANKLIN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No; 3,162,875 December 29, 1964 Armando Silombra It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, lines 8 and 9, for "Claims priority, application Italy, Aug. 12, 1960, 663,112" read Claims priority application Italy, Aug. 12, 1960, 636,112

Signed and sealed thislst day of June 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Altesting Officer Commissioner of Patents 

1. IN AN APPARATUS FOR MANUFACTURING RUBBER BOOTS, A PLURALITY OF HOLLOW PERFORATED LASTS, AN ENDLESS CONVEYOR HAVING A REVERSING LOOP, A PLURALITY OF UNIFORMLY SPACED LAST SUPPORTING JACKS FASTENED ON SAID CONVEYOR, AN AIR PASSAGEWAY IN EACH OF SAID JACKS, MEANS FOR DETACHEDLY CONNECTING THE LAST CAVITIES TO SAID PASSAGEWAYS, A SUCTION PUMP AND DISTRIBUTING MEANS FOR DETACHABLY CONNECTING SAID PUMP TO SAID PASSAGEWAY ON AT LEAST ONE OF SAID JACKS. 